Due in the coming weeks, the baby will be seventh in line to the throne and, it is believed, the first person of mixed race in such a senior position in the history of British royalty.
“I think this baby is going to be hugely important historically because it’s going to break new ground,” royal biographer Claudia Joseph said.
“Whether it’s a girl or a boy, it will be the first Afro-American baby to be born into the royal family.”
With a black mother and white father, Meghan’s ethnicity has never been far from discussions about her relationship with Queen Elizabeth’s grandson - scrutiny that has often been unwelcome.
In late 2016, when he first announced they were dating, Harry issued a rare rebuke to the press, condemning the racial undertones of articles about the couple.
One commentator had written how Meghan would bring “rich and exotic DNA” to the Windsors.
Michelle Ebanks, head of the company that publishes Essence, a US magazine for African-American women, sees the positive.
“Every time we can break a barrier and be, as black people, somewhere we’re not expected to be, that is to be celebrated.
“Because we should not be in a box. Not in a box, not outside a box - there is no box! So, to be royalty should be normal,” Ebanks said.
But Kehinde Andrews, a sociology professor at Birmingham City University who writes on race issues, is less sure that the royal baby indicates any improvement in racial equality.
“Unfortunately, because racism is so bad and so historic and so entrenched... we tend to over-celebrate any symbol that could possibly be good: Barack Obama becoming president, the film Black Panther... whenever it looks like someone is making similar progress - unfortunately we get carried away.“But I think when we actively analyse what’s happened and what’s changed we realise that this is nothing, means nothing at all.” Some British journalists say Meghan has been treated differently from other members of the House of Windsor, citing a difference in attitude towards Kate, the wife of Harry’s elder brother Prince William.
Broadcaster Afua Hirsch, author of Brit(ish): On Race, Identity and Belonging, said ethnicity played a part.
“I would like to see more honesty and introspection in journalists who have repeated some of these tropes about Meghan Markle, and a willingness to at least look at the fact that her treatment has been different,” she said.